Table 2 Classes of modeling assumption constraints (from functional viewpoint)
Subclasses | Subsubclasses | Definition | Examples | |
|---|---|---|---|---|
MAC | Process consideration constraint (PCC) Decision about what kind of physical processes are considered in modeling | Process selection constraint (PS) | Specifies what kind of processes in a physical system are considered/ignored | - Consider (rel-friction(b l, p l)) PA |
- Ignore the change of form/mass of objects which collided PO | ||||
- Consider the heat exchange between two objects (T H > T L) PR | ||||
Out-sourcing constraint (OS) | Ignores a physical process by putting it out of the system and regarding its effect as a boundary condition | - An outer tank which supplies water infinitely PR | ||
- An outer power supply which always supplies 5 V PR | ||||
- Initial velocity v(0) = v 0 PR | ||||
Black-boxing constraint (BB) | Ignores a physical process by putting it in a black box and regarding its effect as a boundary condition | - Consider two parallel-connected springs/resistors as they are or a compound one PO | ||
- Consider two blocks in contact moving with internal force as one PO/CR | ||||
Physical world constraint (PWC) Necessity for maintaining the fundamental law of the physical world | Maintains the fundamental law of the physical world | - Rigid objects never overlap CR | ||
- Mass >0, μ > 0, 0 ≤ e ≤ 1 PR | ||||
- g = 9.8 [m/s/s], gas constant = 8.3 [J/K mol] PR | ||||
Process simplifying constraint (PFC) Convenience for mathematical calculation with the model | Substitutes the simplified process for a complicated (original) process | - Consider the range within which a resistance’s voltage and current are proportional PR | ||
- Consider the behavior of a pendulum with small amplitude as simple harmonic oscillation PR | ||||